Devices and methods for collapsing prosthetic heart valves

ABSTRACT

A crimping tool for use with a collapsible prosthetic valve having a stent frame with a plurality of cell openings, and a valve structure assembled in the stent frame. The crimping tool includes a plurality of resilient tines defining an array around a longitudinal axis of the crimping tool. The array has a first cross-section in an expanded state and a second cross-section less than the first cross-section in a collapsed state. The plurality of tines are adapted to intersect the plurality of cell openings in an assembled position of the crimping tool on the prosthetic valve to prevent pinching of the valve structure by the stent frame as the prosthetic valve is collapsed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a national phase application under 35 U.S.C. §371 ofInternational Application No. PCT/US2010/000475, filed Feb. 19, 2010,published in English, which claims the benefit of the filing date ofU.S. Provisional Patent Application No. 61/208,101, filed Feb. 20, 2009,the disclosures of which are hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention is related to prosthetic heart valve replacement,and more particularly to devices, systems and methods for collapsingprosthetic heart valves.

Prosthetic heart valves that are collapsible to a relatively smallcircumferential size can be delivered into a patient less invasivelythan valves that are not collapsible. For example, a collapsible valvemay be delivered into the patient via a tube-like delivery apparatussuch as a catheter, a trocar, a laparoscopic instrument, or the like.This can avoid the need for a more invasive procedure such as fullopen-chest, open-heart surgery. When the collapsed valve has reached thedesired implant site in the patient (e.g., at or near the annulus of thepatient's heart valve that is to be effectively replaced by theprosthetic valve), the prosthetic valve can be released from thedelivery apparatus and re-expanded to full operating size. Typically, inits full operating size, the prosthetic valve engages adjacent nativetissue of the patient to firmly anchor itself in the patient.

Collapsible prosthetic heart valves typically take the form of a valvestructure mounted on a stent. The stent functions as a frame to securethe valve structure. In order to deliver such a prosthetic heart valveinto a tube-like delivery apparatus and ultimately the patient, theprosthetic heart valve must first be collapsed or crimped to reduce itsdiameter or annular perimeter. Some of the known methods and devices foraccomplishing this are relatively simple. For example, it is well knownin the art to use a funnel attached to a tube-like delivery apparatus tocause a gradual reduction in the diameter or annular perimeter of astent. More complex devices, such as the one disclosed in U.S. Pat. No.7,530,253, can also be utilized. The common goal of each of thesedevices and methods is to collapse the prosthetic heart valve to thesmallest diameter needed (i.e., small enough to fit into the deliverytube of a delivery apparatus) without damaging the valve tissue on thestent.

Despite the various advancements and improvements that have been made tothe crimping process and the overall prosthetic valve replacementprocess, such methods, devices, and systems suffer from similarshortcomings. Among others, valve tissue or the like is often pinched orcaught within the cell openings of the stent or between the struts ofthe stent as the diameter or annular perimeter of the prosthetic heartvalve (i.e., stent and valve tissue therein) is reduced. This phenomenonis best illustrated in FIG. 1, in which such a prosthetic heart valve 10is illustrated in a collapsed condition. As shown, the prosthetic heartvalve 10 includes valve tissue 20 attached to a stent 30. When the valve10 is collapsed, valve tissue 20 becomes caught or pinched between thestruts 31 of the stent 30 and/or within the cell openings 32 of thestent 30. The chance of damage to the tissue 20 as the prosthetic heartvalve 10 is delivered to the implant site exponentially increases whenthis occurs. Furthermore, tissue caught within the openings can preventthe prosthetic heart valve from being reduced to the required orsmallest possible diameter or annular perimeter.

Although known methods of heart valve crimping technology provideimprovements over prior art systems, methods, and devices, there is aneed for further improvements. Among others, the presently claimedinvention addresses some of these shortcomings.

SUMMARY OF THE INVENTION

One aspect of the present invention is directed to a crimping tool foruse with a collapsible prosthetic valve having a stent frame with aplurality of cell openings. The crimping tool includes a handle and aplurality of resilient tines connected to the handle. The plurality oftines define an array around a longitudinal axis, the array having afirst cross-sectional size in an expanded state and a secondcross-sectional size less than the first cross-sectional size in acollapsed state. The plurality of tines are adapted to intersect theplurality of cell openings in an assembled position of the crimping toolon the prosthetic valve. In preferred embodiments, the plurality oftines may define an annular array around the longitudinal axis.

Each of the plurality of tines may have a first portion that extendssubstantially parallel to the longitudinal axis in both the expanded andcollapsed states. Each of the plurality of tines also may have a secondportion disposed between the first portion and the handle, such thateach of the second portions extends at an angle transverse to thelongitudinal axis in the expanded state. The second portions may extendat an angle transverse to the longitudinal axis in the collapsed state.

The plurality of tines may be biased to the expanded state and move tothe collapsed state upon the application of a radially inward force tothe plurality of tines.

The crimping tool may further include a ring slidable relative to theplurality of tines between a first position in which the array is in theexpanded state and a second position in which the array is in thecollapsed state. Moving the ring from the first position to the secondposition exerts a radially inward force on the plurality of tines.

Optionally, the plurality of tines may include a plurality of tinepairs, a distance between the tines in each tine pair being less than adistance between adjacent tine pairs.

Another aspect of the present invention provides a system for prostheticheart valve replacement. The system includes a collapsible prostheticvalve having a stent frame with a plurality of cell openings and acrimping tool. The crimping tool may include a handle and a plurality ofresilient tines connected to the handle and defining an array around alongitudinal axis. The array has a first cross-sectional size in anexpanded state and a second cross-sectional size less than the firstcross-sectional size in a collapsed state. The plurality of tines areadapted to intersect the plurality of cell openings in an assembledposition of the crimping tool on the prosthetic valve.

In preferred embodiments, at least some of the plurality of cellopenings may have apexes and at least some of the plurality of tines areadapted to intersect the apexes of the cell openings in the assembledposition. In the assembled position, each of the cell openings may bedivided by a tine into a first section and a second section.

The prosthetic heart valve may further include a valve structuredisposed within the stent frame. The plurality of tines may bepositioned between the valve structure and the stent frame in theassembled position. Alternatively, the plurality of tines may bepositioned around an exterior of the stent frame in the assembledposition.

Yet another aspect of the present invention provides a method forcollapsing a prosthetic heart valve having a stent frame with aplurality of cell openings, and a valve structure disposed within thestent frame. The method includes providing a crimping tool having aplurality of tines defining an array having a first cross-sectional sizein an expanded state and a second cross-sectional size less than thefirst cross-sectional size in a collapsed state. The crimping tool isassembled to the prosthetic heart valve so that the plurality of tinesintersect the cell openings to divide the cell openings into first andsecond sections. A radially inward force is applied to the prostheticheart valve in order to collapse the prosthetic heart valve while thecrimping tool is assembled thereto.

In embodiments of the prosthetic heart valve in which at least some ofthe cell openings have apexes, the crimping tool may be assembled to theprosthetic heart valve so that at least some of the plurality of tinesintersect the apexes. The plurality of tines may be inserted between thevalve structure and the stent frame, or may be positioned around anexterior of the stent frame.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a portion of a prosthetic heart valvewhich has been crimped using a prior art technique.

FIG. 2 is a perspective view of a crimping tool according to oneembodiment of the present invention, shown in an expanded state.

FIG. 2A is a side elevational view of the crimping tool shown in FIG. 2.

FIG. 3 is a perspective view of the crimping tool of FIG. 2, shown in acompressed state.

FIG. 4 is a perspective exploded view of a system, including acollapsible valve and a crimping tool, according to an embodiment of thepresent invention.

FIG. 5 is a perspective view depicting the system of FIG. 4 in theassembled condition.

FIG. 5A is a cross-sectional view taken along line 5A-5A of FIG. 5.

FIG. 5B is a cross-sectional view taken along line 5B-5B of FIG. 5.

FIGS. 6, 6A, 6B, and 6C are schematic illustrations showing a method ofinserting a prosthetic valve into a catheter in accordance with anembodiment of the present invention.

FIG. 7 is a perspective view of a crimping tool in accordance withanother embodiment of the present invention.

FIG. 8 is a perspective view of a crimping tool in accordance with stillanother embodiment of the present invention.

FIG. 9 is a perspective view of a crimping tool in accordance with yetanother embodiment of the present invention.

DETAILED DESCRIPTION

Referring now to FIG. 2, there is shown a crimping tool 100 according toan illustrative embodiment of the present invention. Crimping tool 100prevents tissue impingement during collapse of a prosthetic heart valvefor delivery into a patient. Crimping tool 100 has a handle or stem 102with a free end 104 and another end 106. A plurality of long, thin tines108 extend in an array from end 106 of the stem. Specifically, tines 108are arranged around the central longitudinal axis 110 along which thestem 102 extends. Tines 108 preferably define an annular array having asubstantially cylindrical configuration around central axis 110, butother configurations including, but not limited to, oval and ellipticalconfigurations are also contemplated herein.

In the embodiment shown, sixteen tines 108 are positioned around thecentral axis 110. However, this number is not critical, and as few astwo tines or more than sixteen tines may be used. The number of tines onthe crimping tool 100 may vary widely based, in part, upon the actualsize of the tines and the number and size of the cell openings formed inthe stent portion of the prosthetic heart valve, as discussed more fullybelow. In preferred embodiments, however, crimping tool 100 will have atleast one tine 108 for each column of cell openings formed around thecircumference of the stent.

Referring to FIG. 2A, each of the tines 108 has a first portion 112 witha tip 114 and a second portion 116. First portions 112 may extendsubstantially parallel to one another and to the central axis 110.Second portions 116, on the other hand, are transverse to central axis110 and converge together at a converging point 120 at which they jointo stem 102. A transition region 124 demarcates the transition betweenthe first portion 112 and the second portion 116 of each tine 108. It isto be appreciated that although the lengths of tines 108 in thepreferred embodiment are uniform, the tines 108 may differ in length,such that one or more of the tines 108 may be shorter or longer than theothers.

The angle between second portions 116 and central axis 110 is notcritical. However, the combination of that angle and the length ofsecond portions 116 must be sufficient that, with tines 108 in theexpanded state described below, the cross-section defined by the firstportions 112 of the tines is large enough to assemble the tines to aprosthetic heart valve in the manner described below.

As shown in FIGS. 2 and 2A, in a preferred embodiment, the tines 108form an annular array around the central axis 110, such that crimpingtool 100 has an overall circular cross-section. The circularcross-section will differ at different locations along the length ofcrimping tool 100. For example, crimping tool 100 defines an annularperimeter P1 around the first portions 112 of the tines 108 which, inthe expanded state, is preferably greater than the annular perimeter P2defined at any point around the second portions 116. Preferably, annularperimeter P1 is substantially uniform along the length of the firstportions 112. Annular perimeter P2, on the other hand, willincrementally decrease along transition region 124 from first portions112 to converging point 120.

Each individual tine 108 may have a circular cross-section along itsentire length. It is to be appreciated, however, that each of the tines108 may possess a different shaped cross-section and/or may vary inshape and/or thickness throughout the length of the tine. For example,each of the tines 108 may have an oval, triangular, rectangular, or anyother cross-section. Further, the thickness of one or more tines 108 intheir first portions 112 may be greater than or less than the thicknessof the same tines 108 in their second portions 116. In addition, theshape and/or thickness of one or more tines 108 may be different fromthe shape and/or thickness of other tines.

The tips 114 of tines 108 are preferably rounded to prevent damage totissue they may contact when inserted into a prosthetic heart valve.Alternatively, the tips 114 may take on any other profile, such as atapered profile, so as to better enable the tines 108 to extend into theprosthetic heart valve, as described in more detail herein.

Each of tines 108 is preferably resilient and biased to the expandedstate, such that the tines 108 may move radially inwardly toward thecentral axis 110 of crimping tool 100 upon the application of anexternal force, as illustrated in the collapsed or compressed state ofthe crimping tool 100 shown in FIG. 3, and then return to theiruncompressed or expanded state shown in FIG. 2 once the crimping toolhas served its purpose and the external force has been removed. It willbe appreciated that tines 108 need not necessarily be formed of aresilient material. Rather, tines 108 may be formed from a relativelyrigid material in first portions 112, and from a resilient material intransition regions 124 and second portions 116. These resilient portionspreferably would be biased to the expanded or uncompressed state shownin FIG. 2. In such arrangement, the second portions 116 will be able todeform upon application of an external force so as to bring the firstportions 112 closer to central axis 110. In a preferred embodiment,however, tines 108 are formed from the same material along their entirelength, the material having sufficient resiliency to cause firstportions 112 to move toward central axis 110 upon the application of anexternal force. As will be discussed in more detail below, any externalforce can be used to cause inward radial movement of the tines 108toward the collapsed state.

The annular perimeter P1 of crimping tool 100 in the uncompressed orexpanded state will be greater than its annular perimeter P1′ in thecompressed or collapsed state. As will be discussed in more detailbelow, the ability of crimping tool 100 to collapse to a smallerperimeter P1′ is necessary for the crimping tool 100 to be compressedalong with a prosthetic heart valve by an amount sufficient to fit intoa delivery catheter or the like.

As noted above, in preferred embodiments, crimping tool 100 may beformed from resilient materials or from materials exhibiting elasticproperties so as to enable tines 108 to reversibly deform. One suchmaterial in this regard is nitinol. Other metals such as stainless steelor the like also may be used, as may tough and resilient polymers, suchas polyurethanes, polyethylenes, nylons or any combination of resins,core or fiber reinforced materials. Furthermore, the crimping tool 100may be entirely or partially coated with a material or materialsselected to provide desirable characteristics. In one embodiment, aswill be explained in greater detail below, to avoid damage to the valvetissue when the crimping tool 100 is inserted into a prosthetic valve,all or portions of the crimping tool 100 may be coated with a materialwhich can minimize friction. Such coating may include, withoutlimitation, fluorinated ethylene propylene (FEP) orpolytetrafluoroethylene (PTFE).

Referring now to FIG. 4, a system 300 for valve replacement is shown inaccordance with the present invention. System 300 includes a collapsible(and re-expandable) prosthetic heart valve 200 and a crimping tool, suchas crimping tool 100 described above.

The collapsible prosthetic heart valve 200 may be any collapsibleprosthetic heart valve known in the art, such as those disclosed incommonly assigned application Ser. No. 11/906,133 filed on Sep. 28, 2007and entitled “Collapsible-Expandible Prosthetic Heart Valves WithStructures For Clamping Native Tissue” and WO 2008/150529 published onDec. 11, 2008 and entitled “Prosthetic Heart Valves,” the disclosures ofwhich are incorporated herein by reference. Preferably, collapsibleprosthetic heart valve 200 includes at least: (1) a frame or stent 202having a distal end 218 and a proximal end 220; and (2) a valve 234formed from softer materials. Valve 234 may include a ring or cuff 204which terminates at or near the proximal end 220 of stent 202, and aplurality of leaflets (not shown) attached inside of the cuff andcooperating with one another to permit blood flow in one directionthrough valve 200, but not in the opposite direction. Cuff 204 and thevalve leaflets may be formed from tissue, such as bovine or porcinepericardial tissue; fabric, such as polyester; or other suitablebiocompatible materials. Any means of attachment known in the art may beused to attach cuff 204 and the valve leaflets to stent 202, such assewing with suture material. It is to be appreciated that when a“collapsible prosthetic heart valve” is referred to herein, it isintended to include at least a stent 202 or other collapsible supportstructure and a valve 234 formed from softer materials and positionedwithin the stent 202. Where needed, specific reference may be madeherein to the specific components of the collapsible prosthetic heartvalve, such as the “cuff,” “leaflets,” or “tissue.”

Stent 202 has a central axis 210 that extends in the length direction,and may have a larger diameter adjacent distal end 218 than the diameteradjacent proximal end 220. This provides stent 202 with an annularperimeter P_(STENT1) at or near its distal end 218 that is greater thanthe annular perimeter P_(STENT2) at or near its proximal end 220.

Stent 202 preferably includes collapsible cell openings 222 definedalong the length and around the circumference of the stent. The cellopenings 222 may all have the same shape or may differ in shape indifferent portions of the stent. For example, as shown in FIG. 4, stent202 may have diamond-shaped cell openings adjacent distal end 218 andgenerally arrow-shaped openings adjacent proximal end 220. As shown,both the diamond-shaped and arrow-shaped cell openings 222 includeapexes 223. It will be appreciated, however, that stent 202 may have anyshape or size of cell openings 222, including those without apexes.

Referring to FIG. 5, the crimping tool 100 is shown positioned withinthe prosthetic heart valve 200. To position the crimping tool 100 withinthe prosthetic heart valve 200, the crimping tool 100 can be manuallyinserted in its uncompressed or expanded state into the prosthetic heartvalve 200. First, a surgeon or technician may grasp the stem 102 of thecrimping tool 100 such that the first portions 112 of the tines 108 facein a direction away from the surgeon. Second, turning to both FIGS. 5and 5A, each of the tines 108 may then be inserted between the cuff 204and stent 202, such that the plurality of tines 108 may directly contactand/or be adjacent the outer surface of the cuff 204 and the innersurface of the stent 202.

When inserting the crimping tool 100 between the cuff 204 and stent 202,it is preferred that each of the plurality of tines 108 be positionedgenerally at or near the longitudinal centerline of a cell opening 222of the stent. With reference to FIG. 5, each of the tines 108 on thecrimping tool 100 may be in radial alignment with the apexes 223 of thecell openings 222 such that the areas of the cell openings 222 aredivided into two distinct sections, i.e., a first section 219 and asecond section 221. It will be appreciated that the tines 108 do nothave to be perfectly aligned with the longitudinal centerlines of thecell openings 222 and/or the apexes of the cell openings. The tines 108may be considered to be appropriately positioned when they cover orblock a portion of the cell openings 222. As will be discussed in moredetail herein, any reduction in the area of the cell openings 222 can bebeneficial.

The tines 108 preferably may be advanced into the prosthetic heart valve200 until the transition regions 124 of the tines are at or near theproximal end 220 of the stent 202. Alternatively, the crimping tool 100may be advanced until it cannot be advanced any further into the stent202, or up until a point where the crimping tool 100 is considered to besufficiently positioned between the cuff 204 and stent 202. Once thefinal position of the crimping tool 100 within the prosthetic heartvalve 200 is established, first portions 112 of the crimping tool 100preferably extend beyond the distal edge 209 of the cuff 204 so that allor substantially all of the cell openings 222 overlying cuff 204 aredivided by at least one tine 108. In the fully assembled position shownin FIG. 5, the second portions 116 of tines 108 and the stem 102 may bepositioned proximally of the proximal end 220 of the stent 202.

With the crimping tool 100 in the assembled position on the prostheticheart valve 200, the prosthetic heart valve is ready to be crimped tothe collapsed state, and with it crimping tool 100. FIGS. 6, 6A, and 6Bschematically illustrate one embodiment of a technique for crimping theprosthetic heart valve/crimping tool combination 224 to the collapsedstate and loading the prosthetic heart valve 200 into a deliverycatheter 236 or the like for eventual insertion into a patient's body.In order for the crimping tool/prosthetic heart valve combination 224 tofit into the delivery catheter 236, the annular perimeters P_(STENT1)and P_(STENT2) of the prosthetic heart valve 200, as well as the overallcircumference of the crimping tool 100, must first be reduced in size.This can be accomplished by loading the crimping tool/prosthetic heartvalve combination 224 into a crimping device capable of radiallycollapsing the crimping tool/prosthetic heart valve combination.Referring to FIG. 6, in one embodiment, a funnel 226 having a largediameter opening 228 at one end and a small diameter opening 232 on theopposite end may be used as the crimping device. The small diameteropening 232 may be connected to the delivery catheter 236 so that as thecollapsed crimping tool/prosthetic heart valve combination 224 emergesfrom the funnel 226, it will immediately enter the delivery catheterwithout any opportunity to radially expand.

To load the crimping tool/prosthetic heart valve combination 224 intothe funnel 226, a surgeon may grasp the stem 102 of the crimping tool100 and use it to maneuver the crimping tool/prosthetic heart valvecombination into the large diameter opening 228 of the funnel 226.Preferably, the prosthetic heart valve 200 is oriented so that thedistal end 218 thereof is the first to enter the large diameter opening228 of funnel 226. This orientation enables the prosthetic heart valve200 to be pushed against the second portions 116 of tines 108 as theheart valve is being collapsed, thereby keeping the heart valve frombeing pulled off of crimping tool 100. This orientation also permitsstem 102 of crimping tool 100 to be accessible for removing the crimpingtool from the heart valve once the heart valve is in place in deliverycatheter 236. The accessibility of the stem 102 also may eliminate theneed for a secondary tool to transport the prosthetic heart valve 200and minimizes unnecessary contact with the tissue of the cuff 204,although a secondary tool can be used if desired.

Referring to FIG. 6A, as the crimping tool/prosthetic heart valvecombination 224 advances through the funnel 226, the converging walls238 of the funnel will apply a compressive force causing the stent 202and tines 108 to begin to collapse and the overall annular perimetersP_(STENT1) and P_(STENT2) to be reduced. Collapsing will continue untilthe crimping tool/prosthetic heart valve combination 224 reaches a sizesufficiently small in diameter to pass through the small diameteropening 232 of the funnel. During the collapsing process, the presenceof tines 108 intersecting cell openings 222 will reduce the continuousopen area of the cell openings, thereby making it more difficult for thetissue cuff 204 to enter the cell opening where it can be pinched by thestruts of stent 202 as it collapses, all of which can be seen in FIG.6B. Thus, in contrast to the prior art method of FIG. 1, the tines 108of crimping tool 100 prevent the tissue of cuff 204 from being pinchedand damaged by the stent 202 as the prosthetic heart valve 200 iscollapsed.

As the crimping tool/prosthetic heart valve combination 224 passesthrough small diameter opening 232, it will exit funnel 226 and enterthe lumen of delivery catheter 236. Advancement of the crimpingtool/prosthetic heart valve combination 224 may continue untilprosthetic heart valve 200 is entirely within delivery catheter 236 oruntil it is determined that crimping tool/prosthetic heart valvecombination 224 is located within the delivery catheter 236 by asufficient amount. When the crimping tool/prosthetic heart valvecombination 224 is at an appropriate location within the deliverycatheter 236, the surgeon may simply pull the crimping tool 100proximally away from the prosthetic heart valve 200 using the stem 102.Referring to FIG. 6C, when the crimping tool 100 has been freed from theprosthetic heart valve 200, only the prosthetic heart valve will remainwithin the delivery catheter 236. As shown, annular perimetersP_(STENT1) and P_(STENT2) will be substantially equal in size, as theentirety of the prosthetic heart valve 200 must fit within the deliverycatheter 236 which, as shown, has a substantially uniform cross-section.

It is to be appreciated that there are numerous crimping devices otherthan funnel 226 that can be utilized in accordance with the presentinvention. For example, without limitation, the HV500 crimper availablefrom Machine Solutions, Inc., also known as an “iris crimper”, is onesuch alternative crimping device.

The above-described collapsing or crimping of the prosthetic heart valve200 and/or crimping tool 100 are preferably elastic deformations. Forexample, the stent 202 and crimping tool 100 are preferably resilientlybiased to have about the same diameter and shape, respectively, in theexpanded state. In such a case, collapsing of the prosthetic heart valve200 and crimping tool 100 can be accomplished by elastic deformation ofthe stent 202 and crimping tool 100, e.g., by applying a force to theprosthetic heart valve and crimping tool directed radially inwardly,such as by confining the stent 202 and crimping tool 100 within apassageway, such as a funnel or tube, having a smaller annular perimeteror diameter than the fully expanded stent and crimping tool. When theprosthetic heart valve 200 and/or crimping tool 100 is pushed or pulledout of the confined passageway, the stent 202 and crimping tool 100 mayre-expand automatically and elastically to their full size. It is to beappreciated that expansion of the stent 202 and/or crimping tool 100 maybe at least partly assisted by other means.

During the crimping process, the overall shape of the annular perimeteror diameter of the stent 202 and crimping tool 100 may remainsubstantially the same in the expanded state and the collapsed state.For example, as shown in FIG. 5A, the crimping tool/prosthetic heartvalve combination 224 has an overall circular cross-section in theexpanded state. In the collapsed state, as shown in FIG. 6A, thecross-section may remain substantially circular. However, this need notbe the case. That is, the crimping tool 100 and/or prosthetic heartvalve 200 may, for example, have an elliptical cross-section in theexpanded state, but may collapse to a substantially circularcross-section.

In an alternative method of loading the prosthetic heart valve/crimpingtool combination 224 into a crimping device, the prosthetic heartvalve/crimping tool combination may be initially compressed using asecondary crimper. Thus, referring to FIG. 7, a crimping tool 100′ mayinclude a ring 238 disposed for advancement along the length of the stem102′ in the direction of arrow A. As the ring 238 is pushed against thesecond portions 116′ of tines 108′, the force exerted by the ring causeseach of the tines to move radially inwardly toward the central axis 110′of the crimping tool 100′. In a preferred arrangement, the ring 238 willbe slid along the tines 108′ when the prosthetic heart valve/crimpingtool combination is first inserted into a crimping device, such asfunnel 226. In such event, the force exerted by the converging walls ofthe funnel, as well as the force applied by the ring 238, will acttogether to collapse the prosthetic heart valve/crimping toolcombination.

FIG. 8 shows another embodiment of a crimping tool 100″ having tines108″ partially inserted within a prosthetic heart valve 200. The tines108″ divide the area of the cell openings 222 of prosthetic heart valve200 into three or more portions. Crimping tool 100″ may include 16 pairsof tines (as opposed to only 16 tines), wherein the tines 108″ within apair are spaced relatively close to one another. The tines 108″ in apair may extend over a single cell opening 222 and divide the area ofthe cell opening into three sections: a first peripheral section 130, asecond middle section 132 between a closely-spaced pair of tines 108″,and a third peripheral section 134. It is to be appreciated that thewidth W of each middle section 132 is defined by the distance betweenthe closely-spaced tines in a pair, which can vary significantly. WidthW may be selected so that a single cell opening 222 is divided intosections of different width or into three sections which aresubstantially the same width. In either case, the distance between thetines in a pair of tines may be less than the distance between adjacentpairs of tines, greater than the distance between an adjacent pair oftines, or the distances may be substantially the same.

Referring to FIG. 9, in yet another embodiment, a crimping tool 100′″may have tines 108′″ that flare outwardly in an expanded state so thatthe crimping tool may be positioned around the exterior of theprosthetic heart valve 200. In such embodiment, the tines 108′″ may beassembled to overlie the cell openings 222 of the stent 202. When thecrimping tool 100′″ is positioned around the prosthetic heart valve 200,the crimping tool 100′″ and prosthetic heart valve 200 may be collapsedusing the methods described above. When the tines 108′″ are collapsed,they may move from an outwardly flared condition to a condition in whichthey are substantially parallel with one another and with thelongitudinal axis 110′″ of the crimping tool.

Although the invention herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent invention. It is therefore to be understood that numerousmodifications may be made to the illustrative embodiments and that otherarrangements may be devised without departing from the spirit and scopeof the present invention as defined by the appended claims.

It will be appreciated that the various dependent claims and thefeatures set forth therein can be combined in different ways thanpresented in the initial claims. It will also be appreciated that thefeatures described in connection with individual embodiments may beshared with others of the described embodiments.

The invention claimed is:
 1. A system for prosthetic heart valvereplacement, comprising: a collapsible prosthetic valve having a stentframe with a plurality of cell openings; and a crimping tool, thecrimping tool including: a handle; and a plurality of resilient tinesconnected to the handle, the plurality of tines including a plurality oftine pairs defining an array around a longitudinal axis, each of thetines being a member of one of the tine pairs, a distance between thetines in each tine pair being less than a distance between adjacent tinepairs, the array having a first cross-sectional size in an expandedstate and a second cross-sectional size less than the firstcross-sectional size in a collapsed state, the plurality of tines beingadapted to intersect the plurality of cell openings in an assembledposition of the crimping tool on the prosthetic valve.
 2. The system asclaimed in claim 1, wherein each of the plurality of tines has a firstportion, the first portion of each of the plurality of tines extendingsubstantially parallel to the longitudinal axis in both the expanded andcollapsed states.
 3. The system as claimed in claim 2, wherein each ofthe plurality of tines has a second portion disposed between the firstportion and the handle, each of the second portions extending at anangle transverse to the longitudinal axis in the expanded state.
 4. Thesystem as claimed in claim 3, wherein each of the second portionsextends at an angle transverse to the longitudinal axis in the collapsedstate.
 5. The system as claimed in claim 1, wherein each of theplurality of tines is biased to the expanded state and moves to thecollapsed state upon the application of a radially inward force to theplurality of tines.
 6. The system as claimed in claim 1, furthercomprising a ring slidable relative to the plurality of tines between afirst position in which the array is in the expanded state and a secondposition in which the array is in the collapsed state, movement of thering from the first position to the second position exerting a radiallyinward force on the plurality of tines.
 7. The system as claimed inclaim 1, wherein at least some of the plurality of cell openings haveapexes, and at least some of the plurality of tines are adapted tointersect the apexes of the cell openings in the assembled position. 8.The system as claimed in claim 1, wherein the prosthetic heart valvefurther includes a valve structure disposed within the stent frame, andthe plurality of tines are positioned between the valve structure andthe stent frame in the assembled position.
 9. A system for prostheticheart valve replacement, comprising: a collapsible prosthetic valvehaving a stent frame with a plurality of cell openings; and a crimpingtool, the crimping tool including: a handle; and a plurality ofresilient tines connected to the handle, the plurality of tinesincluding a plurality of tine pairs defining an array around thelongitudinal axis, a distance between a first tine in each tine pair andan adjacent tine in the tine pair being less than a distance between thefirst tine in each tine pair and another tine adjacent to the firsttine, the array having a first cross-sectional size in an expanded stateand a second cross-sectional size less than the first cross-sectionalsize in a collapsed state, the plurality of tines being adapted tointersect the plurality of cell openings in an assembled position of thecrimping tool on the prosthetic valve.